Ford Pick-Ups/Expedition/Navigator 1997-2000

Diagnostic Monitor


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Fig. Fig. 1 The air bag diagnostic monitor continually checks the SRS system to detect any trouble or fault

The diagnostic monitor is located behind the center of the instrument panel, under the radio. The diagnostic monitor serves no purpose in the firing of the air bag(s). The main purpose of the diagnostic monitor is to monitor the operational status of the system through continual checks of the system's circuits. In the event of a fault detected, the diagnostic monitor will illuminate the air bag indicator and flash out a DTC. All codes are double digit and if a code is flashed, it can be read as follows: a flash-flash-flash, one-second pause, flash-flash, three-second pause, is a code 32. If numerous codes are stored, they will flash after the three second pause, if only one code is stored, the same flash sequence will begin again. In the event of a air bag indicator bulb failure, an audible tone will be emitted from the diagnostic monitor. this tone is a series of five sets of five beeps, this is code 55 indicating the indicator bulb is out and in addition the air bag system may require service.

The diagnostic monitor also contains the back-up power supply. In the event of a impact severing the battery or other electrical sources to the air bag system, the back up power supply contains enough power to deploy the air bag(s). The diagnostic monitor contains several small capacitors that store power. The back-up power supply must be discharged before air bag service can be performed.